1------------------------------------------------------------------------------
2--                                                                          --
3--                        GNAT RUN-TIME COMPONENTS                          --
4--                                                                          --
5--                               S Y S T E M                                --
6--                                                                          --
7--                                 S p e c                                  --
8--                            (Compiler Version)                            --
9--                                                                          --
10--          Copyright (C) 1992-2018, Free Software Foundation, Inc.         --
11--                                                                          --
12-- This specification is derived from the Ada Reference Manual for use with --
13-- GNAT. The copyright notice above, and the license provisions that follow --
14-- apply solely to the  contents of the part following the private keyword. --
15--                                                                          --
16-- GNAT is free software;  you can  redistribute it  and/or modify it under --
17-- terms of the  GNU General Public License as published  by the Free Soft- --
18-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
19-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
20-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
21-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
22--                                                                          --
23-- As a special exception under Section 7 of GPL version 3, you are granted --
24-- additional permissions described in the GCC Runtime Library Exception,   --
25-- version 3.1, as published by the Free Software Foundation.               --
26--                                                                          --
27-- You should have received a copy of the GNU General Public License and    --
28-- a copy of the GCC Runtime Library Exception along with this program;     --
29-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
30-- <http://www.gnu.org/licenses/>.                                          --
31--                                                                          --
32-- GNAT was originally developed  by the GNAT team at  New York University. --
33-- Extensive contributions were provided by Ada Core Technologies Inc.      --
34--                                                                          --
35------------------------------------------------------------------------------
36
37--  This version of System is a generic version that is used in building the
38--  compiler. Right now, we have a host/target problem if we try to use the
39--  "proper" System, and since the compiler itself does not care about most
40--  System parameters, this generic version works fine.
41
42pragma Restrictions (No_Implicit_Dynamic_Code);
43--  We want to avoid trampolines in the compiler, so it can be used in systems
44--  which prevent execution of code on the stack, e.g. in windows environments
45--  with DEP (Data Execution Protection) enabled.
46
47pragma Restrictions (No_Finalization);
48--  Use restriction No_Finalization to avoid pulling finalization (not allowed
49--  in GNAT) inside sem_spark.adb, when defining type Perm_Tree_Access as an
50--  access type on incomplete type Perm_Tree_Wrapper (which is required for
51--  defining a recursive type).
52
53package System is
54   pragma Pure;
55   --  Note that we take advantage of the implementation permission to make
56   --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
57   --  2005, this is Pure in any case (AI-362).
58
59   pragma No_Elaboration_Code_All;
60   --  Allow the use of that restriction in units that WITH this unit
61
62   type Name is (SYSTEM_NAME_GNAT);
63   System_Name : constant Name := SYSTEM_NAME_GNAT;
64
65   --  System-Dependent Named Numbers
66
67   Min_Int               : constant := Long_Long_Integer'First;
68   Max_Int               : constant := Long_Long_Integer'Last;
69
70   Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
71   Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
72
73   Max_Base_Digits       : constant := Long_Long_Float'Digits;
74   Max_Digits            : constant := Long_Long_Float'Digits;
75
76   Max_Mantissa          : constant := 63;
77   Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
78
79   Tick                  : constant := 0.01;
80
81   --  Storage-related Declarations
82
83   type Address is private;
84   --  Note that we do NOT add pragma Preelaborable_Initialization in this
85   --  version of System, since it is used for the compiler only, and typical
86   --  earlier bootstrap compilers don't support this pragma. We don't need
87   --  it in this context, so there is no problem in omitting it.
88   Null_Address : constant Address;
89
90   Storage_Unit : constant := Standard'Storage_Unit;
91   Word_Size    : constant := Standard'Word_Size;
92   Memory_Size  : constant := 2 ** Standard'Address_Size;
93
94   --  Address comparison
95
96   function "<"  (Left, Right : Address) return Boolean;
97   function "<=" (Left, Right : Address) return Boolean;
98   function ">"  (Left, Right : Address) return Boolean;
99   function ">=" (Left, Right : Address) return Boolean;
100   function "="  (Left, Right : Address) return Boolean;
101
102   pragma Import (Intrinsic, "<");
103   pragma Import (Intrinsic, "<=");
104   pragma Import (Intrinsic, ">");
105   pragma Import (Intrinsic, ">=");
106   pragma Import (Intrinsic, "=");
107
108   --  Other System-Dependent Declarations
109
110   type Bit_Order is (High_Order_First, Low_Order_First);
111   Default_Bit_Order : constant Bit_Order :=
112                         Bit_Order'Val (Standard'Default_Bit_Order);
113   pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
114
115   --  Priority-related Declarations (RM D.1)
116
117   Max_Priority           : constant Positive := 30;
118   Max_Interrupt_Priority : constant Positive := 31;
119
120   subtype Any_Priority       is Integer      range  0 .. 31;
121   subtype Priority           is Any_Priority range  0 .. 30;
122   subtype Interrupt_Priority is Any_Priority range 31 .. 31;
123
124   Default_Priority : constant Priority := 15;
125
126private
127
128   type Address is mod Memory_Size;
129   Null_Address : constant Address := 0;
130
131   --------------------------------------
132   -- System Implementation Parameters --
133   --------------------------------------
134
135   --  These parameters provide information about the target that is used by
136   --  the compiler. They are in the private part of System, where they can be
137   --  accessed using the special circuitry in the Targparm unit whose source
138   --  should be consulted for more detailed descriptions of the individual
139   --  switch values.
140
141   --  This version of system.ads is used only for building the compiler.
142   --  We really ought to use the proper target system (i.e. the one that
143   --  corresponds to the host for the compiler), but that causes as yet
144   --  unsolved makefile problems. For the most part the setting of these
145   --  parameters is not too critical for the compiler version (e.g. we
146   --  do not use floating-point anyway in the compiler).
147
148   AAMP                      : constant Boolean := False;
149   Backend_Divide_Checks     : constant Boolean := False;
150   Backend_Overflow_Checks   : constant Boolean := False;
151   Command_Line_Args         : constant Boolean := True;
152   Configurable_Run_Time     : constant Boolean := False;
153   Denorm                    : constant Boolean := True;
154   Duration_32_Bits          : constant Boolean := False;
155   Exit_Status_Supported     : constant Boolean := True;
156   Fractional_Fixed_Ops      : constant Boolean := False;
157   Frontend_Layout           : constant Boolean := False;
158   Machine_Overflows         : constant Boolean := False;
159   Machine_Rounds            : constant Boolean := True;
160   Preallocated_Stacks       : constant Boolean := False;
161   Signed_Zeros              : constant Boolean := True;
162   Stack_Check_Default       : constant Boolean := False;
163   Stack_Check_Probes        : constant Boolean := False;
164   Stack_Check_Limits        : constant Boolean := False;
165   Support_Aggregates        : constant Boolean := True;
166   Support_Composite_Assign  : constant Boolean := True;
167   Support_Composite_Compare : constant Boolean := True;
168   Support_Long_Shifts       : constant Boolean := True;
169   Always_Compatible_Rep     : constant Boolean := True;
170   Suppress_Standard_Library : constant Boolean := False;
171   Use_Ada_Main_Program_Name : constant Boolean := False;
172   Frontend_Exceptions       : constant Boolean := False;
173   ZCX_By_Default            : constant Boolean := True;
174
175   --  Obsolete entries, to be removed eventually (bootstrap issues)
176
177   Front_End_ZCX_Support     : constant Boolean := False;
178   High_Integrity_Mode       : constant Boolean := False;
179   Long_Shifts_Inlined       : constant Boolean := True;
180   Functions_Return_By_DSP   : constant Boolean := False;
181   Support_64_Bit_Divides    : constant Boolean := True;
182   GCC_ZCX_Support           : constant Boolean := True;
183
184end System;
185